

import math





def dot(a, b):

    sum=0;

    c=zip(a,b)

    for item in c:

        sum+=item[0]*item[1]

        return sum

def mo(a):

    for i in a:

        sum+=i*i

    return sum**0.5



def angle(a,b):

    ji=dot(a,b)

    amo=mo(a)

    bmo=mo(b)

    cos=ji/(amo*bmo)
    hudu=math.acos(cos)

    jiaodu=hudu*180/math.pi

    return jiaodu

    print(hudu)